Monday, April 27, 2009

The first genuinely warm day of Spring. The Sun opens up the landscape into a buzzing, multi-hued repository of beauty and intricately detailed physical process. The garden is stratified by colour: three blood-red tulips surge vertically against an emerald background of lawn, hedge and tree, themselves shouldering an aquamarine sky.

Taking a walk to the local stream, limitless complexity abounds. Where the flow is shallow, and the bed is pebbly, a series of undulations appear in the surface flow; standing waves perhaps? Fronds of vegetation protrude into the waterway, and small vortices spin off their tips, passing a short distance diagonally down the streamflow. In places, the flow is narrow, and vegetation chokes both sides; here, the vortices cross-hatch the surface.

Some parts of the stream are silent and languid; others tinkle and babble, and here the flow is turbulent. Sudden irregularities and constrictions cause small waves to break, and jets to impact the water, trapping bubbles of air; cavitation creates bubbles of water vapour where the water impacts upon rock and stone; the bubbles oscillate, creating sound waves in the water, which propagate to the surface, and thence transmit to the air as a tranquilising murmur.

Each square metre of this totally unremarkable watercourse, is worthy of its own treatise; each unit area deserves its own magnus opus from a fluid dynamicist.

Thursday, April 23, 2009

Environmental Graffiti recalls some of the commercial products of the early 20th Century which, (perhaps unwisely), extolled the medicinal properties of radium.

These include radium face-cream, radium chocolate, radium suppositories, radium toothpaste, and most splendidly, the radiendocrinator, which was intended to be placed over the endocrine glands to 'invigorate sexual virility'. Men were advised to place the instrument under the scrotum at night like an 'athletic strap'.

Radiate as directed, indeed.

The inventor of this fabulous product was one William J. Bailey, who claimed to regularly use his own products, and to have drunk more radium water than any other living man.

Saturday, April 18, 2009

I take it to be an unassailable truth that what Taoism, Confucianism, Zen Buddhism, and the writings of Carlos Castenda have in common, they have in common with quantum mechanics. (R.I.G. Hughes)

One could be forgiven for assuming, from name alone, that 'Victor Stenger' is either a science-fiction writer from the 1950s, or a porn-star. On the latter front, one might be tempted to imagine that his first pet was called 'Victor', and his current place of residence is 'Stenger Avenue'.

In fact, Victor J.Stenger is a retired physicist, and one who has taken in recent years to writing a number of books promoting the naturalistic world-view, and denouncing religion and pseudo-science.

Stenger duly has a new book out, Quantum Gods, which identifies the ongoing need many people have to see something mystical in quantum theory. Stenger discriminates between quantum theology, in which people see evidence for God in quantum theory, and quantum spirituality, in which people see evidence for the fundamental role of the mind in the universe.

Whilst Stenger is correct to debunk this type of quantum mysticism, there seems little evidence that he has a knowledge of either philosophy or the philosophy of science, and this complacency leads him into error. For example, in his paper Where did the laws of physics come from?, Stenger argues that the laws of physics are determined by: (i) the empirical measurement data; and (ii) the need for coordinate-invariant laws.

Yet, to pose the question, 'Why does the universe possess the laws that we observe it to possess, and not some other possible laws?', is to imagine the possible existence of other universes with sets of empirical data satisfying different laws from our own. To argue that the laws of physics are the way they are, because the empirical data (and coordinate-independence) has constrained them to be such, is to mis-understand the problem at hand.

In another paper, A scenario for a natural origin of our universe, Stenger announces: "What I will show is that a mathematical model of the origin of our universe based on no more than...well-established theories can be precisely specified. This model is essentially the 'no boundary' model proposed over twenty years ago by Hartle and Hawking."

Again, however, Stenger's paper demonstrates an ignorance of the relevant literature in the philosophy of physics, some of which is somewhat less enthusiastic about the Hartle-Hawking ansatz...

The principles of scholarship dictate that a professional researcher should be acquainted with all of the relevant literature before putting pen to paper, yet Stenger, and for that matter, most of the physicists who write about philosophical subjects, do so with a blithe disregard for this principle. Curious.

Tuesday, April 14, 2009

At universities and funding agencies...tenure and grant committees take decisions based on narrow criteria (focusing on publication lists, citations and impact factors) or on specific plans for near-term results, all of which inherently favour those working in established fields with well-accepted paradigms.

Mark Buchanan considers the prospects for encouraging greater scientific innovation in the April issue of Physics World. He suggests that scientific discoveries satisfy a power law distribution, that "the largest events are hugely disproportionate in their consequences. In the metaphor of Nassim Nicholas Taleb’s 2007 best seller The Black Swan, it is not the normal events, the mundane and expected 'white swans' that matter the most, but the outliers, the completely unexpected 'black swans'."

Physicist Eric Weinstein proposes that scientific innovation could be encouraged by the creation of a financial options market in scientific ideas: "Weinstein’s point is that markets, in theory at least, work efficiently and — putting the current financial meltdown to one side — lead to the accurate valuation of products. They exploit the 'wisdom of crowds', as a popular book of the same title recently put it."

Yes, putting the current financial meltdown to one side. Apart from that.

Friday, April 10, 2009

Computers are incredibly fast, accurate, and stupid. Human beings are incredibly slow, inaccurate, and brilliant. Together they are powerful beyond imagination. (Einstein)

Michael Schmidt and Hod Lipson have apparently developed an automated search algorithm which discovers physical laws and conservation equations from scratch. The algorithm scrutinises the experimental data extracted from the motion capture of physical systems, and reproduces the classical laws which explain the data. Or, as The Guardian claimed, Schmidt and Lipson have developed a 'Eureka machine'.

In a technique Schmidt and Lipson refer to as 'symbolic regression', their algorithm searches the space of possible mathematical expressions until it finds analytical expressions which reproduce the empirical data. Starting from algebraic operations and simple analytical functions such as sine and cosine, the algorithm randomly re-combines previous equations and parameters, and tests each set of expressions for accuracy against the empirical data, until it reaches a desired level of accuracy. Schmidt and Lipson's algorithm was able to converge on the Hamiltonians, Lagrangians and force laws of classical physical systems, including non-linear systems.

As an aside, if it is true that civilization is a non-linear classical physical system, then Schmidt and Lipson's algorithm could perhaps be applied to the data generated by human history, to discover the fundamental laws of cliodynamics. The difficulties of extracting empirical data in this case, where there is only historical documentation rather than motion capture, are obviously not to be underestimated. Moreover, whilst Schmidt and Lipson are able to pre-specify what the state variables of their systems are - they direct their software to look at positions, velocities and accelerations - in the case of cliodynamics, a central difficulty is identifying what the state variables actually are.

Schmidt and Lipson's work raises a number of funamental issues for both the philosophy of science, and for physics. The fact that their algorithm converges on unique, self-consistent laws, seems to undermine the purported underdetermination of theory by data, a popular bone of contention in the philosophy of science.

It also looks like this work is the first serious step down a road which will considerably alter, and perhaps reduce the creative opportunities for physicists. There would still be, of course, the need to develop such algorithms, to prepare the input data, and to interpret the output. And it should also be emphasised that, from the perspective of mathematical physics, the primary creative task is the discovery of mathematical structures, not the discovery of the laws satisfied by the variables embedded in those structures. An algorithm which discovers the mathematical structures necessary to represent the physical world is a step beyond the work of Schmidt and Lipson. Nevertheless, whilst mathematical physicists might take this consolation, the long-term prospects may not be quite as rosy for their counterparts in theoretical physics.

Wednesday, April 08, 2009

It might come as something of a surprise to Ross Brawn and his colleagues at Williams and Toyota, but the double-decker diffusers used by their respective Formula 1 teams, depend for their efficacy upon ontologically parasitic immaterial particulars.

The underneath of a Formula 1 car consists of a reference plane astride the centreline of the car, and a step plane 50mm above it on either side. The upper deck of a double-decker diffuser is fed by airflow from apertures located underneath the car, in the vertical wall joining the step plane and the reference plane. The legality of these diffusers will be the subject of an FIA appeal hearing next Tuesday, and a central part of the argument concerns whether these apertures constitute fully enclosed holes in a continuous surface, or merely slots between two separate surfaces.

Thus, at next week's hearing, I suggest that the plaintiffs (Ferrari, Renault, BMW and Red Bull) should call Achille C. Varzi as an expert witness. Varzi, we might recall, is a Professor of Philosophy at Columbia University, who is a world authority on the nature of holes. Varzi points out that holes are particular entities, with specific sizes and shapes, but they are made of nothing. Hence, philosophically speaking, holes are immaterial particulars. They are also ontologically parasitic, in the sense that they depend upon other, material entities, for their existence.

Whether or not the apertures used by the diffuser-gang are holes or not, is something that only Varzi can determine with authority. In a right and proper world, Achille Varzi could conceivably determine the outcome of this year's World Championship.

Exceptionally, the train tonight allows him half a carriage to himself. He has been making this journey for the past 12 years. In the slanting summer light, when the smell of cut grass enters the windows from across the open countryside, he falls prey to feelings of nostalgia. He puts his feet up on the seat opposite and is carried back to other evenings which looked almost exactly like this one, which were of the same temperature and clarity, but happened when his mother was still alive, before his children were born, when he was not yet divorced. He contemplates all that has been difficult, unnecessary and regrettable but from a position of distance, with a calm and poignant vantage point over his imperfections and missed opportunities, as though his life were a bad sentimental film and he its half sympathetic, half repugnant hero. He has reached the age of reminiscence, though right now, somewhere in the scattered houses outside, there is a 16-year-old boy for whom this will be the one central hot summer of longing and discovery, the one remembered in 30 years on a train which is not yet made and remains as iron ore in the red scrub of the Western Australian desert.

Everyone's favourite glabrous, middle-brow, populist television philosopher, Alain de Botton is back with a book on The Pleasures and Sorrows of Work. For a fairly harmless, genial individual, de Botton seems to generate large quantities of opprobrium amongst professional philosophers and literary types. Mary Margaret McCabe (no relation, as far as I'm aware), gave The Consolations of Philosophy an absolute pasting back in 2000, complaining that

"Philosophy, on this view, is the self-help science, the art of success, whose imperatives are heard throughout the book against barely disguised autobiographical themes of social awkwardness, disastrous sexual activity and failure in love.

"De Botton fails entirely to see that if reflection is to be thus directed, then, corrupted by the exigencies of practicality, it ceases to have the kind of reflective distance which makes it work."

"In the culture of the market economy, we miss the fact that philosophy is valuable in and by itself; and this is the culture which will destroy not only the independence of philosophy, but the humanities entire."

On the contrary, there's no justification for making such assumptions about what philosophy can and cannot be, and philosophy as a whole is sufficiently robust to withstand the odd attempt at popular applicability.

Nevertheless, it's true that the actual philosophy in de Botton's books is quite shallow. It is, rather, the poignancy and the wit of de Botton's observations on life which become their real attraction. In de Botton's discourse on the art of travel, he advises readers to avoid compulsive photography on holiday, and instead, to try drawing landmarks in pencil. By so doing, one processes all the intricate detail and structure through one's own my mind, and in the bargain, one generates a uniquely personal rendition, rather than a generic, disposal photo.

And on the subject of work, it would be wrong to dismiss an author capable of suggesting that the "start of work means an end to freedom, but also to doubt, intensity and wayward desires... How satisfying it is to be held in check by the assumptions of colleagues, instead of being forced to contemplate, in the loneliness of the early hours, all that one might have been, and now never will be."

Monday, April 06, 2009

This week's Nature journal features an interview with James Acord, reputedly the only private individual in the world with a license to possess and handle radioactive materials. James even has his license number tattooed on the back of his neck (Washington State Radioactive Materials License # WN-10407-1).

(Presumably, the need for a license is a matter of degree, given that our own bodies contain radioactive potassium-40, and given that the walls of most buildings contain the radioactive isotopes from the natural uranium-238 and thorium-232 decay chains).

Acord creates sculptures out of radioactive materials, but his latest project seems to be more a means of creating plutonium-239 in the garden shed. He explains in Nature that he has taken the americium-241 from a smoke detector, and coupled it to an emerald stone. Americium-241 is a source of alpha particles, and when alpha particles collide with the beryllium in the stone (emerald is a variety of the mineral beryl Be3Al2(SiO3)6), it produces neutrons. Acord has therefore basically produced a conventional americium-beryllium neutron source from home-made materials.

Acord then moderates the neutrons with a hydrogenous material, which could easily have been water or plastic, but which Acord has ingeniously chosen to be a 6cm slice of beeswax. The moderated neutrons then impinge upon the glazing to be found on certain ceramics from the 1940s. The glazing contains a form of uranium-oxide, and a certain fraction of the uranium-238 nuclei will absorb the moderated neutrons, and thereby transform to uranium-239. The latter will then undergo beta decay to neptunium-239, which in turn will beta decay to plutonium-239.